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1.
Rats experimentally infected with Taenia taeniaeformis were followed-up until 14 weeks post inoculation with eggs (PIE) by hepatic ultrasonographic (US) image and serum antibody response analyses. Parasitic cysts could be imaged as small (2 mm in diameter) anechoic areas with or without a parenthesis-like echogenic small line from two weeks PIE. Immunoblot analysis using antigens from oncospheres (TtO), 30-day-old (TtM-30) and 300-day-old metacestodes (TtM-300) revealed that: (1) these three different developmental stages showed their own unique patterns suggesting the presence of stage-specific antigens; (2) faint IgM antibody responses to some components of TtO and TtM-30 or TtM-300 could be detected from one and two weeks PIE, respectively, and (3) IgG responses to some major components of both TtO and TtM-300, and TtM-30 were easily detected from four and five weeks PIE onwards, respectively. Both TtO and TtM (especially TtM-300) appeared to be highly useful for detection of antibody responses in experimentally infected rats. Due to the easiness in preparation of antigens, fully developed metacestodes may be the best candidate antigens for serodiagnosis. These results strongly suggest that both US image and antibody analyses using antigens from fully developed metacestodes are useful for detection of the early stage of cysticercosis in laboratory animal model.  相似文献   

2.
Activated oncospheres of Taenia ovis were incubated for 24 h or 48 h at 37-5 degress C in Medium 858 alone or in Medium 858 enriched with 20% lamb serum or foetal calf serum. Antigens contained in the supernatant medium from these incubations were concentrated, emulsified in Freund's incomplete adjuvant and injected intramuscularly into lambs. These lambs developed a very high level of immunity to subsequent challenge infection with T. ovis eggs.  相似文献   

3.
The efficiencies of an enzyme method and the sodium hypochlorite method in hatching eggs of Taenia solium (Henan strain) were compared. The viability of the hatched oncospheres was determined by staining with trypan blue. For the former method, the hatching rate and viability percentage were 85.7% and 79.7%, respectively. The corresponding figures for the latter method were 97.9% and 86.7%, respectively. These findings indicate that the sodium hypochlorite method is a simple, efficient and practical method for hatching eggs of Taenia solium.  相似文献   

4.
Heterocypris incongruens (RAMD.) was selected as an intermediate host, having emerged as the main host for Diorchis stefanskii Czapl. in experimental conditions. It was found that the index of infective activity for larvae of D. stefanskii was high on the first day, amounting to 50-54%, with an extensity of infection of 100%. The infective activity of larvae declined slowly but steadily at the low temperature (5 degrees C). Oncospheres retained their infective activity for more than 2.5 months. In contrast, in culture at 18-20 degrees C and 25 degrees C, the infective activity of larvae had declined rapidly only a few days into the experiment. The irrevocable loss of tapeworm infectivity occurred at temperatures of -5 degrees C and +38 degrees C, at which 100% of oncospheres died.  相似文献   

5.
由于聚焦离子束(Focused Ion Beam,简称FIB)显微镜的最新运用,材料科学得以迅速发展。钢铁行业中,聚焦离子束技术不仅可以不断将涂料和钝化层变薄,而且特别适用于多相或成分混杂的和/或多孔材料的透射电子显微镜(Transmission Electron Microscope,简称TEM)薄片制备。四年前,在ArcelorMittal Gent设备上安装了三重束聚焦离子束仪器。随后利用该仪器对大量的各种各样的材料进行筛选和/或处理,以进一步进行TEM分析。FIB技术成功运用于图层、基体和界面研究领域。比如:1)图层应用:厚度均匀性、缺损性及腐蚀研究;2)衬底分析:裂纹扩展、晶界及晶粒取向;3)界面分析:金属间(化合的)相、扩散和偏聚,外延研究。由于FIB仪器的高成本性以及配套需要的专业操作技能,毫无疑问局限了其在钢铁研究中的日常应用。不过,仍然可以从聚焦离子束制备样品的独特方式中获得许多经济效益,比如更短的样品制备时间、对抽样区域的选择性,当然还有人为因素的影响极其有限。因此,通常情况下,FIB样品制备成为唯一一种可以用于制备透射电子显微镜薄片的途径。FIB同TEM的联用分析技术开启了一个化学的、微结构和晶体信息的新世界,这种新领域将在以下研究中得以体现:1)锌 - 铝 -镁涂层的共晶相表征;2)富铬钝化层的缺损学研究;3)耐候钢的结构组成; 4)无锌涂层的微结构:铝/镁显示为纳米晶体状的铝镁多相结构。  相似文献   

6.
Two antibodies, one monoclonal and one polyclonal, were produced and used to identify Taenia solium eggs, using the enzyme-linked immuno-electrotransfer blot technique (EITB). Different life-stages of Taenia solium and T. saginata, including eggs from gravid proglottids recovered, post-treatment, from patients infected with the tapeworms, and eggs of Diphyllobothrium pacificum and Hymenolepis nana from other patients were tested with these antibodies. The monoclonal antibody only recognized the eggs and immature proglottids of T. solium. The polyclonal antibody, however, not only reacted with the eggs, cysticerci and immature proglottids of T. solium but also with the eggs and immature proglottids of T. saginata. The sensitivity and specificity of the EITB were both 100% using the monoclonal antibody but only 78% and 60%, respectively, using the polyclonal antibody. Diagnostic bands for T. solium eggs corresponded to proteins of 22.5 kDa using the polyclonal antibody and 22.5-37 kDa using the monoclonal antibody. Species-specific fluorescence was obtained with an anti-T. solium monoclonal antibody which bound to egg-derived oncospheres of T. solium but not to those of T. saginata.  相似文献   

7.
Our laboratory developed an isolated perfused superior mesenteric arterial vascular bed preparation to study and correlate vascular smooth-muscle mechanics with associated biochemical events. This preparation provides consistent dose-dependent contractile responses, contains most of the superior mesenteric artery as well as first-, second-, and third-generation arterioles, and has been used for concurrent functional and biochemical analysis of vascular smooth muscle. Preparations isolated from Sprague-Dawley rats produced rapid, dose-related vasoconstrictor responses to norepinephrine (NE) and KCl, while appearing to be unresponsive to periarterial nerve stimulation. Endothelial relaxations to bolus doses of acetylcholine (ACh) in the presence of a constant infusion of NE (10 microM) were limited, producing reductions of perfusion pressures of <25%. Receptor-binding studies conducted to evaluate alpha1-adrenoceptor subtypes revealed high- and low-affinity binding sites composing 91 and 9% of the overall population, respectively. A 60-s time course for contractile response and inositol 1,4,5-triphosphate (IP3) production revealed a significant but transient increase of IP3 that paralleled the contractile response generated by using bolus injections of NE (30 microg). This preparation offers the capacity to conduct perfusion studies investigating vasoconstrictor responses, as well as biochemical studies including receptor-binding and second-messenger assays in the same tissue.  相似文献   

8.
Cytochrome b-559 is an integral component of photosystem II complexes from both plants and cyanobacteria. However, the number of cytochrome b-559 associated with the photosystem II reaction center has been the subject of controversy. Some studies have concluded that there is one heme equivalent of cytochrome b-559 per reaction center, some studies have found two, and some studies have reported intermediate values. Most of the previous experiments have used only one method to quantitate the antenna size of the preparation. In this study, we compare the cytochrome b-559 content in a cyanobacterial and a plant photosystem II preparation. The plant preparation is derived from spinach, and previous work has shown that it has an antenna size of approximately 100 chlorophylls [MacDonald, G. M., & Barry, B. A. (1992) Biochemistry 31, 9848-9856]. The cyanobacterial preparation is from Synechocystis sp. PCC 6803, and previous work has shown that it has an antenna size of approximately 60 chlorophylls [Noren, G. H., Boerner, R. J., & Barry, B. A. (1991) Biochemistry 30, 3943-3950]. Both preparations are isolated through the use of ion-exchange chromatography, and both preparations are monodisperse in the same nonionic detergent. In our comparative study, we quantitate antenna size by three different methods. Our work shows that, depending on the method used to estimate antenna size, the oxygen-evolving spinach photosystem II preparation contains 0.82-1.0 cytochrome b-559 per reaction center, while the oxygen-evolving cyanobacterial preparation contains 1.5-2.1 cytochrome b-559 per reaction center.  相似文献   

9.
Recent studies suggest a significant contribution of the pulmonary circulation to the perfusion of large airways. In this study we used anesthetized ventilated sheep (n = 19) to determine the functional contribution of the pulmonary circulation to airway smooth muscle. We performed sequential intravenous challenge with methacholine chloride (MCh; 0.25-2.5 mg/ml) to determine airway resistance (Raw) changes in the intact animal, after bronchial artery cannulation that essentially removed bronchial arterial delivery of MCh, and in an isolated lung preparation. After blocking the vagal reflex component of this response, we found that intravenous MCh in the intact preparation resulted in an average 2.2 +/- 0.5 cmH2O.l-1.s increase (181%) in Raw. After prevention of bronchial arterial delivery of MCh, Raw increased by 0.8 +/- 0.3 cmH2O.l-1.s (64%; P < 0.01 compared with intact preparation). In the isolated lung preparation, Raw increased by 0.6 +/- 0.2 cmH2O.l-1.s (63%; P < 0.01 compared with intact preparation). These results demonstrate that in sheep, the bronchial artery provides the major route for delivery of intravenously administered agonists to airway smooth muscle. Considering the large dilutional effect of an intravenously administered agonist by the time it reaches the bronchial artery, we conclude that the pulmonary component of agonist delivery to large airways is < 10% and unlikely to play a major physiological role.  相似文献   

10.
The aim of this study was to determine the influence of an oil preparation with increased n-3 fatty acids content on the serum lipid profile and clinical condition of cats with miliary dermatitis. The studies were performed on 22 cats of various breeds and both sexes, aged between 3 and 7 years, that had been fed a balanced diet, based on beef meat for the previous 6 months. The animals were divided into four groups: I, five clinically healthy cats; II, five clinically healthy cats, receiving 1 ml of oil preparation with food for 6 weeks; III, seven nonpruritic cats with miliary dermatitis, without treatment; and group IV, five nonpruritic cats with miliary dermatitis, receiving 1 ml of oil preparation per day with food for 6 weeks. Every 2 weeks all cats were clinically examined. Determination of the serum lipid profile and composition of the oil preparation was performed using gas chromatography. The concentration of total cholesterol (CHL), high-density lipoprotein (HDL) fraction and triacylglycerols (TG) were determined spectrophotometrically. In three sick animals, the dermatological signs disappeared completely. In cats with miliary dermatitis, who did not receive the oil preparation, the ratio of cholesterol and HDL to triacylglycerols was reversed compared with healthy cats and sick animals which had received the oil preparation. The addition of the oil preparation lowered the content of saturated fatty acids in serum, in particular palmitic acid, and increased the content of unsaturated acids, linolenic, eicosapentaenoic (EPA, n-3) and docosahexaenoic acid (DHA, n-3). Simultaneously, a nonsignificant rise in arachidonic acid (AA, n-6) and a decrease in dihomo-gamma-linolenic acid (DGLA, n-6) were found. These observations indicate that cats with miliary dermatitis require an increased amount of n-3 fatty acids in the diet. This was proved not only by the observed changes in the serum lipid profile but also by the clinical improvement.  相似文献   

11.
PROBLEM: In vitro studies have demonstrated microfractures in resected roots after root end cavity preparation with ultrasonic tips. Such microfractures are of concern; however, they may be artifacts. OBJECTIVES: To assess the incidence of microfractures after ultrasonic root end cavity preparation in situ. STUDY DESIGN: Fifty-two roots in two cadavers were endodontically treated, the soft tissues excised, and the root ends exposed and resected. The resected root surfaces were replicated with polyvinylsiloxane impressions. Root end cavities were prepared with ultrasonic tips, then impressed a second time. The roots were retrieved; 25 were processed for direct SEM examination as were both the impressions of each root. The specimens were examined by stereomicroscope and scanning electron microscope. RESULTS: In the impressions, the resected and prepared surfaces appeared irregular, but none demonstrated microfractures. In contrast, 15 retrieved roots showed microfractures. CONCLUSIONS: Ultrasonic root end cavity preparation in situ did not cause root microfractures, and the impression technique could be clinically usable with minor modifications.  相似文献   

12.
An amino peptidase enzyme preparation obtained from Aspergillus niger was subjected to a series of toxicological tests to document the safety for use as a processing aid for food. The enzyme preparation was examined for subacute and subchronic oral toxicity, and mutagenic potential. No evidence of oral toxicity or mutagenicity was found. Administration of the amino peptidase enzyme preparation at doses of 500, 1000 and 2000 mg/kg body weight/day for 90 days did not induce noticeable signs of toxicity. The no-observed-adverse-effect level (NOAEL) of the enzyme preparation in the subchronic toxicity study was 2000mg/kg body weight/day (equivalent to 1152 PHEA units/kg body weight/day). It can be concluded that no safety concerns were identified in the studies conducted with this amino peptidase enzyme preparation derived from Aspergillus niger and produced under controlled fermentation conditions.  相似文献   

13.
Rifamycin oxidase of Curvularia lunata was immobilized on alginate gel. The pH and temperature optima of the immobilized enzyme preparation were 6.5 and 50 degrees C, respectively. Transformation reaction was carried out with the immobilized enzyme preparation. It took 8 h for the complete transformation of rifamycin B (10 g/L) to rifamycin S. The immobilized enzyme preparation was found to be mechanically weak even in the presence of CaCl2 in the reaction mixture. Reusability studies showed that the catalyst can not be repeatedly used very effectively.  相似文献   

14.
A meta-analysis of studies on preparation for medical procedures and pain evaluated the relative effects of sensory, procedural, and combined sensory-procedural preoperational information on coping outcomes. Results indicated that, in contrast to sensory information, procedural information provided no significant benefits over control group instruction. Combined sensory-procedural preparation, however, yielded the strongest and most consistent benefits in terms of reducing negative affect, pain reports, and other-rated distress. The meta-analytic results are consistent with the dual process preparation hypothesis, which proposes that the information combination is optimal because procedural details provide a map of specific events while sensory information facilitates their interpretation as nonthreatening. It is concluded that a combined preparation is the preferred clinical option. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

15.
A recombinant L ferritin preparation, lyophilized in ampoules and designated 94/572, was evaluated by 18 laboratories in 9 countries for its suitability as an International Standard (IS). The preparation was assayed in a wide range of in-house and commercial immunoassays against the 2nd IS for ferritin (of spleen origin; 80/578). The immunological reactivity of the recombinant material was similar to that of the 2nd IS for ferritin in the majority of assays and demonstrated adequate stability in accelerated degradation studies. On the basis of the results presented here, the WHO Expert Committee on Biological Standardization established 94/572 as the 3rd IS for ferritin, recombinant.  相似文献   

16.
Estrogen replacement is usually administered as an oral preparation. Concerns have been expressed about the impact these oral preparations have on hepatic function. This paper reviews studies of one nonoral preparation that delivers estradiol into the systemic circulation by use of a transdermal system. Support for this delivery system for treating menopausal symptoms and, potentially, for avoiding side effects is presented.  相似文献   

17.
As a preclinical step to human studies with combined stem cell-enriched peripheral leukocytes and organ transplantation from the same donor, a series of studies in rats was undertaken. These studies indicated that Lewis rats infused intravenously with major histocompatibility complex-incompatible (from Brown-Norway rats), stem cell-enriched peripheral leukocyte preparation alone never developed graft-versus-host disease (GHVD). However, GVHD invariably manifested in all animals a few days after the kidney was transplanted in rats that had been previously primed with stem cell-enriched peripheral leukocytes from the same kidney donor strain. GVHD was prevented by substituting the crude preparation of stem cell-enriched peripheral leukocytes with a purified preparation that was almost completely free of T lymphocytes. However, in these latter experiments all rats rejected their kidney graft within 10 days from the surgery. In rats previously given the crude stem cell-enriched peripheral leukocyte preparation, perioperative administration of the fusion protein CTLA4lg also prevented GVHD and prolonged kidney graft survival up to 106 to 175 days. By contrast, animals with kidney transplants, which were given CTLA4lg without stem cells, rejected their grafts within 35 days. All together, these findings may possibly contribute to the creation of rationally designed strategies of combining organ and bone marrow from the same donor to enhance mixed chimerism and prolong survival after organ transplantation.  相似文献   

18.
研究了硅热还原三硫化二铈制备单硫化铈的新方法。理论计算确定了反应的热力学条件,试验确定了反应温度、时间和还原剂硅过量值等反应条件。分析了反应过程的动力学影响因素并提出了二次反应法减少单硫化铈产物中杂相三硫化二铈的方法,研究了单硫化铈中残留的还原剂硅的分离净化方法。与文献报道的其它方法比较,结果表明:与铝热还原法和碳热还原法相比,硅热还原法制备的单硫化铈纯度高——杂相三硫化二铈低,残留的硅容易分离。与稀土金属和硫黄直接反应法、氢化铈和三硫化二铈合成法以及电解法比较,硅热还原法所需的设备更为简单实用。  相似文献   

19.
Lien, Ruthruff, Remington, & Johnston (2005) reported residual switch cost differences between stimulus–response (S–R) pairs and proposed the partial-mapping preparation (PMP) hypothesis, which states that advance preparation will typically be limited to a subset of S–R pairs because of structural capacity limitations, to account for these differences. Alternatively, the failure-to-engage (FTE) hypothesis does not allow for differences in probability of advance preparation between S–R pairs within a set; it accounts for residual switch cost differences by assuming that benefits of advance preparation may differ between S–R pairs. Three Experiments were designed to test between these hypotheses. No capacity limitations of the type assumed by the PMP hypothesis were found for many participants in Experiment 1. In Experiments 2 and 3, no evidence was found for the dependency of residual switch cost differences between S–R pairs on response-stimulus interval that is predicted by the PMP hypothesis. Mixture-model analysis of reaction times distributions in Experiment 3 provided strong support for the FTE hypothesis over the PMP hypothesis. Simulation studies with a computational implementation of the FTE hypothesis showed that it is able to account in great detail for the results of the present study. Together, these results provide strong evidence against the PMP hypothesis and support the FTE hypothesis that advance preparation probabilistically fails or succeeds at the level of the task set. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

20.
A series of studies assessed perceptual-motor transmission of stimulus information by measuring lateralization of movement-related brain potentials in a choice reaction task with no-go trials. When stimuli varied in shape and size, lateralized potentials on no-go trials suggested that easily recognized shape information was used to initiate motor preparation and that this preparation was aborted when size analysis signified that the response should be withheld. This indicates that movement preparation can begin once partial perceptual information about a stimulus becomes available, contrary to an assumption of fully discrete models of information processing. By contrast, when stimuli varied only in size, no evidence for preliminary response preparation was obtained, contrary to an assumption of fully continuous models but consistent with asynchronous discrete coding models (J. Miller, 1982, 1988). (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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